A cDNA encoding a human endothelium-derived vasoconstrictor peptide, endothelin, was isolated from a human placenta cDNA library. The nucleotide sequence of this cDNA clone showed that the primary structure of the human preproendothelin has 212 amino acid residues and is highly homologous to porcine preproendothelin, and that human endothelin is identical with porcine endothelin.

Neuromedin U is a bioactive peptide isolated originally from the porcine spinal cord. We recently identified neuromedin U as the cognate ligand for the orphan G protein-coupled receptor FM-3. In this study, we isolated cDNA coding for a novel G protein-coupled receptor, TGR-1, which was highly homologous with FM-3. We found that neuromedin U specifically and clearly elevated the extracellular acidification rates, arachidonic acid metabolite release, and intracellular Ca 2؉ mobilization in Chinese hamster ovary cells expressing TGR-1. Radiolabeled neuromedin U specifically bound with high affinity to membrane fractions prepared from these cells. These results show that TGR-1, like FM-3, is a specific and functional receptor for neuromedin U. We analyzed TGR-1 mRNA tissue distribution in rats using quantitative reverse transcription-polymerase chain reaction and found it to considerably differ from that of FM-3 mRNA. TGR-1 mRNA was primarily expressed in the uterus, suggesting that TGR-1 mediates the contractile activity of neuromedin U in this tissue. The identification of specific and functional receptor subtypes for neuromedin U will facilitate the study of their physiological roles and the search for their specific agonists and antagonists.The bioactive peptides neuromedin U-8 and U-25 were originally isolated from the porcine spinal cord based on their powerful contractile activity in the uterine smooth muscle of rats (1, 2). Since then, neuromedin U has been found to show various biological activities including the elevation of blood pressure and the induction of adrenocorticotropin and corticosterone release in vivo in rats (1, 3-6). Applying our previously described strategy to identify endogenous ligands for orphan G protein-coupled receptors (GPCRs) 1 (7-9), we recently succeeded in demonstrating that the orphan GPCR, FM-3, a homologue of the neurotensin (NT) and growth hormone secretagogue receptors, is a specific and functional receptor for neuromedin U (10). When FM-3 was expressed in Chinese hamster ovary (CHO) cells, neuromedin U induced specific and clear elevation of extracellular acidification rates, arachidonic acid metabolite (AA) release, and intracellular Ca 2ϩ mobilization. Radiolabeled neuromedin U specifically bound with high affinity to membrane fractions prepared from these cells. Our analyses for FM-3 mRNA expression levels using quantitative reverse transcription-polymerase chain reaction (RT-PCR) indicated that FM-3 mRNA was expressed highly in the small intestine and lung of rats, but only very low levels were detected in the uterus. Nonetheless neuromedin U has reportedly shown very strong contractile activity (1, 2), and numerous binding sites have been detected in rat uterine tissue (11, 12). We considered that this discrepancy might be due to the existence of an unknown receptor subtype for neuromedin U in the rat uterus. We therefore searched for another neuromedin U receptor subtype in addition to FM-3.In this paper, we report on the isolation of human and rat cDNA encoding a n...

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The DNA sequence of the part of the Mycoplasma capricolum genome that contains the genes for 20 ribosomal proteins and two other proteins has been determined. The organization of the gene cluster is essentially the same as that in the S10 and spc operons of Escherichia coli. The deduced amino acid sequence of each protein is also well conserved in the two bacteria. The G + C content of the M. capricolum genes is 29%, which is much lower than that of E. coli (51%). The codon usage pattern of M. capricolum is different from that of E. coli and extremely biased to use of A and U(T): about 91% of codons have A or U in the third position. UGA, which is a stop codon in the "universal" code, is used more abundantly than UGG to dictate tryptophan.

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